If you are getting nothing at all when trying to power up, then my guess it would be indeed the PSU, or maybe the motherboard.
You can power up the PSU without a motherboard (unless things have changed a lot recently) by connecting two pins on the 24-pins connector that goes into the motherboard using something like a paperclip
If your unit is not giving any signs of powering on you can test it using the Paperclip test. You will need: 1x metal paperclip Steps: 1. Flip the switch on the back of your power supply to the off position "0". 2. Disconnect you...
support.antec.com
Don't forget to disconnect the PSU from everything first. With that you should have an idea if the PSU is working or not.
And yeah, Cyberpunk appears to be a "killer" of systems.... over here my old 7700K was really struggling and getting
very hot, so I decided stop playing until after some patches and an upgrade on my part.